1. Field of the Invention
The present invention is related to electronic controls for an actuator and more particularly to an electronic control which supplies both saturated signal and small signal control for an actuator.
2. Description of Relating Art
Actuators of many types are controlled using feedback control. The control logic may be embodied in analog control circuits or digital controllers. Digital control me be accomplished using many different types of devices, such as programmable logic controllers (PLC) or microprocessor based electronic control modules.
One example of an actuator is a brake caliper of a braking system of a motor vehicle. The brake caliper is actuated by a controller. Typically, an operator instructs the controller to apply the brake through operation of a brake pedal. The force applied by the brake caliper is modulated through modulation of the brake pedal.
Actuation of the brakes may be divided into a plurality of phases, for example, initial application of the brakes or application of the brakes to bring the vehicle to a complete stop, modulation of the brakes to slow the vehicle to a desired speed, and release of the brakes. During the first and last of these phases, it is desirable to apply maximum voltage and current to the actuator (in a forward or reverse direction). During the middle phase, brake force is modulated as a function of brake pedal position.
However, previous systems controlled actuation of the brake caliper using a single control function during each of these phases.
The present invention is aimed at one or more of the problems identified above.
In one aspect of the present invention, a controller for controlling an actuator in response to an input signal is provided. The controller includes a first control block and a second control block. The first control block receives the input signal, detects an operating condition of the input signal, and responsively produces an operating condition signal. The operating condition signal has a first value if the operating condition of the input signal is in a small signal mode and a second value if the operating condition of the input signal is in a saturated mode. The second control block has a small signal portion and a saturation portion. The second control block is adapted to receive the input signal and the operating condition signal and responsively deliver to the actuator a control signal. The small signal portion and the saturation portion are adapted to produce a small signal control signal and a saturation control signal, respectively, as a function of the input signal. The control signal is equal to the small signal control signal if the operating condition signal is equal to the first value and is equal to the saturation control signal if the operation condition signal is equal to the second value.
In another aspect of the present invention, a controller for controlling a brake caliper for a brake system of a motor vehicle in response to an input signal is provided. The controller includes a first control block and a second control block. The first control block receives the input signal, detects an operating condition of the input signal, and responsively produces an operating condition signal. The operating condition signal has a first value if the operating condition of the input signal is in a small signal mode and a second value if the operating condition of the input signal is in a saturated mode. The second control block has a small signal portion and a saturation portion. The second control block is adapted to receive the input signal and the operating condition signal and responsively deliver to the brake caliper a control signal. The small signal portion and the saturation portion are adapted to produce a small signal control signal and a saturation control signal, respectively, as a function of the input signal. The control signal is equal to the small signal control signal if the operating condition signal is equal to the first value and is equal to the saturation control signal if the operation condition signal is equal to the second value.